What is a bubble machine?

That's a battery operated machine that blows bubbles instead of a child having to blow through a wand

Usually a battery operated electronic device that you add bubble solution to and it automatically blows bubbles until the liquid runs out, at which point it would be refilled. I hope that helps.

I guess it would be something that produces bubbles when you blow through it, or a machine that makes lots of bubbles automatically.

I've seen 2 kinds for sale in the past. One u blow in to. The other takes batteries. Im not sure if Walmart sales both ...bye

I have no idea sorry maybe the thing in the kids department that blows bubbles they had one at my sons wedding for the kids .